Optical glass, precision press molding preform and method of manufacturing the same, optical element and method of manufacturing the same

Abstract

Provided are optical glass exhibiting a refractive index (nd) in a range of 1.75 to 1.87, an Abbé number (νd) in a range of 80 to 45, and excellent low-temperature softening properties even when not incorporating Th2O5 as well as permitting a low production cost; a precision press molding preform and an optical element comprised of such glass; a method of manufacturing the preform; and a method of manufacturing the optical element. The optical glass comprises, in a molar percent, 30 to 45 percent of B2O3, 2 to 15 percent of SiO2, 10 to 20 percent of La2O3, 1 to 10 percent of TiO2, 10 to 30 percent of ZnO, 2 to 15 percent of Li2O, higher than 0 percent and 10 percent or less of WO3, 0 to 15 percent of Nb2O5, and 0 to 10 percent of ZrO2, wherein the total amount of the above-mentioned components is higher than 95 percent, the glass exhibits a refractive index (nd) in a range of 1.75 to 1.87, and an Abbé number (νd) in a range of 80 to 45. The precision press molding preform and the optical element are comprised of the glass. In the method of manufacturing a precision press molding preform, the preform comprised of the optical glass is formed. The method of manufacturing an optical element employs the precision press molding preform.

Dependencies are inferred from the claim text.